Item:print_for_table_def() uses QT_TO_SYSTEM_CHARSET to print
the DEFAULT expression into FRM file during CREATE TABLE.
Therefore, the expression is encoded in utf8 in FRM.
get_field_default_value() erroneously used field->charset() to
print the DEFAULT expression at SHOW CREATE TABLE time.
Fixing get_field_default_value() to use &my_charset_utf8mb4_general_ci instead.
This makes DEFAULT work in the way way with:
- virtual column expressions:
if (field->vcol_info)
{
StringBuffer<MAX_FIELD_WIDTH> str(&my_charset_utf8mb4_general_ci);
field->vcol_info->print(&str);
- check constraint expressions:
if (field->check_constraint)
{
StringBuffer<MAX_FIELD_WIDTH> str(&my_charset_utf8mb4_general_ci);
field->check_constraint->print(&str);
Additional cleanup:
Fixing system_charset_info to &my_charset_utf8mb4_general_ci in a few
places to make non-BMP characters work in DEFAULT, virtual column,
check constraint expressions.
MDEV-28127 did is_equal() which compared vcol expressions
literally. But another table vcol expression is not equal because of
different table name.
We implement another comparison method is_identical() which respects
different table name in vcol comparison. If any field item points to
table_A and compared field item points to table_B, such items are
treated as equal in (table_A, table_B) comparison. This is done by
cloning table_B expression and renaming any table_B entries to table_A
in it.
value.type_handler()->result_type()'
failed in virtual bool Item_param::get_date(THD*, MYSQL_TIME*, date_mode_t)
This is a cleanup for MDEV-25593. When binding from NULL, IGNORE or DEFAULT,
value.type_handler should be set to &type_handler_null,
to satisfy the DBUG_ASSERT in Item_param::get_date().
When binding to NULL, DEFAULT or IGNORE from an Item value, Item_param did not
change m_type_handler, so its value remained from the previous bind.
Thid led to DBUG_ASSERTs in Item_param::get_date() and
Timestamp_or_zero_datetime_native_null.
Fix:
Set Item_param::m_type_handler to &type_handler_null when
binding from an Item returning NULL.
This patch also fixes MDEV-35427.
Item_char_typecast::val_str_generic() uses Item::str_value as a buffer.
Item::val_str_ascii() also used Item::str_value as a buffer.
As a result, str_value tried to copy to itself.
Fixing val_str_ascii() to use a local buffer instead of str_value.
Two problem solved:
1) Item_default_value makes a shallow copy so the copy
should not delete field belong to the Item
2) Item_default_value should not inherit
derived_field_transformer_for_having and
derived_field_transformer_for_where (in this variant
pushing DEFAULT(f) is prohibited (return NULL) but
if return "this" it will be allowed (should go with
a lot of tests))
Search conditions were evaluated using val_int(), which was wrong.
Fixing the code to use val_bool() instead.
Details:
- Adding a new item_base_t::IS_COND flag which marks Items used
as <search condition> in WHERE, HAVING, JOIN ON, CASE WHEN clauses.
The flag is at the parse time.
These expressions must be evaluated using val_bool() rather than val_int().
Note, the optimizer creates more Items which are used as search conditions.
Most of these items are not marked with IS_COND yet. This is OK for now,
but eventually these Items can also be fixed to have the flag.
- Adding a method Item::is_cond() which tests if the Item has the IS_COND flag.
- Implementing Item_cache_bool. It evaluates the cached expression using
val_bool() rather than val_int().
Overriding Type_handler_bool::Item_get_cache() to create Item_cache_bool.
- Implementing Item::save_bool_in_field(). It uses val_bool() rather than
val_int() to evaluate the expression.
- Implementing Type_handler_bool::Item_save_in_field()
using Item::save_bool_in_field().
- Fixing all Item_bool_func descendants to implement a virtual val_bool()
rather than a virtual val_int().
- To find places where val_int() should be fixed to val_bool(), a few
DBUG_ASSERT(!is_cond()) where added into val_int() implementations
of selected (most frequent) classes:
Item_field
Item_str_func
Item_datefunc
Item_timefunc
Item_datetimefunc
Item_cache_bool
Item_bool_func
Item_func_hybrid_field_type
Item_basic_constant descendants
- Fixing all places where DBUG_ASSERT() happened during an "mtr" run
to use val_bool() instead of val_int().
The 10.5->10.6 merge commit 3bc98a4ec4 casts the arg to an int16
pointer in set_extraction_flag_processor(). This matched the previous
commit c76eabfb5e where set_extraction_flag was changed to have int16 arg
instead of int.
The commit a5e4c34991 for MDEV-29363 added a call to
set_extraction_flag_processor on IMMUTABLE_FL (MARKER_IMMUTABLE in 10.6).
The subsequent 10.5->10.6 merge f071b7620b did not cast the flag
to int16 when merging this change.
The result is big-endian processors cleared the immutable
flag rather than set the flag, resulting in MDEV-29363
being unfixed on big-endian processors.
New runtime diagnostic introduced with MDEV-34490 has detected
that `Item_int_with_ref` incorrectly returns an instance of its ancestor
class `Item_int`. This commit fixes that.
In addition, this commit reverts a part of the diagnostic related
to `clone_item()` checks. As it turned out, `clone_item()` is not required
to return an object of the same class as the cloned one. For example,
look at `Item_param::clone_item()`: it can return objects of `Item_null`,
`Item_int`, `Item_string`, etc, depending on the object state.
So the runtime type diagnostic is not applicable to `clone_item()` and
is disabled with this commit.
As the similar diagnostic failures are expected to appear again
in the future, this commit introduces a new test file in the main suite:
item_types.test, and new test cases may be added to this file
Reviewer: Oleksandr Byelkin <sanja@mariadb.com>
There are 3 diff in result:
1) NULL value from SELECT
Due to incorrect truncating of the hex value, incorrect value is
written instead of original value to the view frm. This results in reading
incorrect value from frm, so eventual result is NULL.
2) 'Name_exp1' in column name (in gis.test)
This was because the identifier in SELECT is longer than 64 characters,
so 'Name_exp1' alias is also written to the view frm.
3)diff in explain extended
This was because the query plan for view protocol doesn't
contain database name. As a fix, disable view protocol for that particular
query.
The `Item` class methods `get_copy()`, `build_clone()`, and `clone_item()`
face an issue where they may be defined in a descendant class
(e.g., `Item_func`) but not in a further descendant (e.g., `Item_func_child`).
This can lead to scenarios where `build_clone()`, when operating on an
instance of `Item_func_child` with a pointer to the base class (`Item`),
returns an instance of `Item_func` instead of `Item_func_child`.
Since this limitation cannot be resolved at compile time, this commit
introduces runtime type checks for the copy/clone operations.
A debug assertion will now trigger in case of a type mismatch.
`get_copy()`, `build_clone()`, and `clone_item()` are no more virtual,
but virtual `do_get_copy()`, `do_build_clone()`, and `do_clone_item()`
are added to the protected section of the class `Item`.
Additionally, const qualifiers have been added to certain methods
to enhance code reliability.
Reviewer: Oleksandr Byelkin <sanja@mariadb.com>
from HAVING
The bug is caused by refixing of the constant subquery in pushdown from
HAVING into WHERE optimization.
Similarly to MDEV-29363 in the problematic query two references of the
constant subquery are used. After the pushdown one of the references of the
subquery is pushed into WHERE-clause and the second one remains as the part
of the HAVING-clause.
Before the represented fix, the constant subquery reference that was going to
be pushed into WHERE was cleaned up and fixed. That caused the changes of
the subquery itself and, therefore, changes for the second reference that
remained in HAVING. These changes caused a crash.
To fix this problem all constant objects that are going to be pushed into
WHERE should be marked with an IMMUTABLE_FL flag. Objects marked with this
flag are not cleaned up or fixed in the pushdown optimization.
Approved by Igor Babaev <igor@mariadb.com>
Improve performance of queries like
SELECT * FROM t1 WHERE field = NAME_CONST('a', 4);
by, in this example, replacing the WHERE clause with field = 4
in the case of ref access.
The rewrite is done during fix_fields and we disambiguate this
case from other cases of NAME_CONST by inspecting where we are
in parsing. We rely on THD::where to accomplish this. To
improve performance there, we change the type of THD::where to
be an enumeration, so we can avoid string comparisons during
Item_name_const::fix_fields. Consequently, this patch also
changes all usages of THD::where to conform likewise.
The crash is caused by the attempt to refix the constant subquery during
pushdown from HAVING into WHERE optimization.
Every condition that is going to be pushed into WHERE clause is first
cleaned up, then refixed. Constant subqueries are not cleaned or refixed
because they will remain the same after refixing, so this complicated
procedure can be omitted for them (introduced in MDEV-21184).
Constant subqueries are marked with flag IMMUTABLE_FL, that helps to miss
the cleanup stage for them. Also they are marked as fixed, so refixing is
also not done for them.
Because of the multiple equality propagation several references to the same
constant subquery can exist in the condition that is going to be pushed
into WHERE. Before this patch, the problem appeared in the following way.
After the first reference to the constant subquery is processed, the flag
IMMUTABLE_FL for the constant subquery is disabled.
So, when the second reference to this constant subquery is processed, the
flag is already disabled and the subquery goes through the procedure of
cleaning and refixing. That causes a crash.
To solve this problem, IMMUTABLE_FL should be disabled only after all
references to the constant subquery are processed, so after the whole
condition that is going to be pushed is cleaned up and refixed.
Approved by Igor Babaev <igor@maridb.com>
Fixing applying the COLLATE clause to a parameter caused an error error:
COLLATION '...' is not valid for CHARACTER SET 'binary'
Fix:
- Changing the collation derivation for a non-prepared Item_param
to DERIVATION_IGNORABLE.
- Allowing to apply any COLLATE clause to expressions with DERIVATION_IGNORABLE.
This includes:
1. A non-prepared Item_param
2. An explicit NULL
3. Expressions derived from #1 and #2
For example:
SELECT ? COLLATE utf8mb_unicode_ci;
SELECT NULL COLLATE utf8mb_unicode_ci;
SELECT CONCAT(?) COLLATE utf8mb_unicode_ci;
SELECT CONCAT(NULL) COLLATE utf8mb_unicode_ci
- Additional change: preserving the collation of an expression when
the expression gets assigned to a PS parameter and evaluates to SQL NULL.
Before this change, the collation of the parameter was erroneously set
to &my_charset_binary.
- Additional change: removing the multiplication to mbmaxlen from the
fix_char_length_ulonglong() argument, because the multiplication already
happens inside fix_char_length_ulonglong().
This fixes a too large column size created for a COLLATE clause.
The problem was that Item_default_value::associate_with_target_field
assigned passed as argument field as an argument which changed argument
in case of default() call with certain field (i.e. deault(field)).
There is no way to get wrong field in constructor so we will not reassign
parameter.
Some fixes related to commit f838b2d799 and
Rows_log_event::do_apply_event() and Update_rows_log_event::do_exec_row()
for system-versioned tables were provided by Nikita Malyavin.
This was required by test versioning.rpl,trx_id,row.
Queries that select concatenated constant strings now have
colname and value that match. For example,
SELECT '123' 'x';
will return a result where the column name and value both
are '123x'.
Review: Daniel Black
UPDATE statement that is run in PS mode and uses positional parameter
handles columns declared with the clause DEFAULT NULL incorrectly in
case the clause DEFAULT is passed as actual value for the positional
parameter of the prepared statement. Similar issue happens in case
an expression specified in the DEFAULT clause of table's column definition.
The reason for incorrect processing of columns declared as DEFAULT NULL
is that setting of null flag for a field being updated was missed
in implementation of the method Item_param::assign_default().
The reason for incorrect handling of an expression in DEFAULT clause is
also missed saving of a field inside implementation of the method
Item_param::assign_default().
Thanks to Yury Chaikou for finding this problem (and the fix).
Reviewed-by: Monty <monty@mariadb.org>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
